int led = 13;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(led, OUTPUT);
}

void loop() {
digitalWrite(led, HIGH);
Serial.println("led on");
delay(1000);

digitalWrite(led, LOW);
Serial.println("led off");
delay(1000);
}